This invention relates to a biologically pure strain of magnetotactic bacteria and to products derived therefrom.
Magnetotactic bacteria were first reported by Blakemore in Science, 190, 377 (1975). Several species of these bacteria, extracted from both fresh water and marine environments, were observed to orient and to swim in a preferred direction relative to the geomagnetic field. Magnetotactic bacteria from the Northern Hemisphere were observed to orient and swim towards the North, while it was predicted (and later confirmed) that magnetotactic bacteria from the Southern Hemisphere would orient and swim towards the South. Reversal of the ambient magnetic field, e.g., by Helmholz coils, caused the cells to reverse directions within one second. Killed cells also oriented in uniform fields as low as 0.1 G. In this and other respects, the cells behaved like single magnetic domains in a ferromagnetic material.
The magnetotactic behavior of the bacteria was attributed to cellular iron localized in crystal-like particles, 1000 to 1500 A long within the bacteria. As reported above, the bacteria contained these iron-rich particles arranged in chains. Each cell had one or two of these chains, consisting of five to ten particles apiece. Clumps of the particles were also observed outside of the cells. It was speculated that the iron-containing particles equip the bacteria with a permanent ferromagnetic dipole moment.